Cutting blade with self-contained guard



April 14, 1970 c. A. ITEN 3,505,734

CUTTING BLADE WITH SELF-CONTAINED GUARD Filed Feb. 28, 196B 2Sheets-Sheet 1 April 14, 1970 l c. A. lTr-:N

CUTTING BLADE WITH SELF-CONTAINED GUARD 2 Sheets-Sheet 2 Filed Feb. 28,1968 United States Patent O 3,505,734 CUTTING BLADE WITH SELF-CONTAINEDGUARD Clemens A. Iten, Staunton, Va., assignor to Philip MorrisIncorporated, New York, N.Y., a corporation of Virginia Filed Feb. 28,1968, Ser. No. 709,126 Int. Cl. B26b Z1 54 U.S. Cl. 30--346.58 6 ClaimsABSTRACT OlF THE DISCLOSURE This disclosure is directed to a cuttingblade such as a razor blade having a self-contained permanently attachedguard whereby the blade holder may be of simple economical form and thenormal guards or combs or other cutting edge protective means built intothe blade holder may be omitted, the guard here comprising a threadhaving successively spaced portions arranged to extend beyond thecutting edge the spacing and thread diameter dimensions being ofcritical values, the thread being of a material which is flexible toenable it to be readily formed into the desired shape but havingsuitable stiffness and resistance to being severed when engaged againstthe sharpened blade edge.

THE PRIOR ART IN GENERAL The prior art contains many and variedproposals for the direct application in permanent or detachable forms ofguard means. One class comprises the so-called hair Shapers where theguard usually has teeth of a coarse or u'ide dimension with wide spacesin between such as to receive readily the hair such devices beingadapted for coarse operation and not for cutting close to the skin norleaving a clean shaven surface.

A patent to Dickenson 1,035,548 issued Aug. 13, 1912, discloses aso-called straight razor having a long blade foldable into a slot in thehandle, the blade having spirally wound thereon a wire or thread ofother material to form a guard according to the description. However,the wire turns are shown as widely spaced with no indication orrecognition of any criticality in the spacing of the successive loops ofthe wire nor of the wire diameter nor of any relation between thespacing and the wire diameter.

Other patents such as the more recent one to Ferrara 3,263,330 issuedAug. 2, 1966, disclose the application to a .razor blade cutting edge ofa sheet material which has preformed therein a row of holes the sheetbeing folded over the edge on a line bisecting the successive holesleaving a strip over the edge between holes. Such an arrangementpresents practical difficulties in satisfactorily applying such a sheetstrip, one factor being that the sheet sections between holes need to beof substantial width for applying and securing the sheet in place buttoo wide intervening sections between holes tend to iron down and passover some of the hairs,

SUMMARY OF THE INVENTION It has been found that a cutting blade with aselfcontained guard in the form of a thread having portions or sectionsarranged at and extending beyond the cutting edge and generallyperpendicular to the cutting edge is surprisingly effective, dependableand safe in removing hairs close to the skin which employs incombination thread diameters and spacing between adjacent threadsections of certain critical values including the relation of the threaddiameter and spacing one to the other. With the proper dimensions andrelations gouging is avoided and danger of nicking of the skin isgreatly minimized. A

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razor blade of this type can be mounted in a simple economical holderwhich does not require accurate geometry or close tolerances in therelationship of parts. The guards or combs normally built into the bladeholder are not required at least insofar as safety and avoidance of skincuts are concerned, although they may be embodied for other functionssuch as aiding to set up the hairs for the blade cutting. The blade canbe freely handled `with little danger of cutting the handler or damageto the blade cutting edge from contact with hard surfaces. With theselected critical thread diameters and spacing between adjacent threadportions at the cutting edge the blade can be drawn across the skinlogitudinally of the edge without cutting. In general a close safe shavecan be obtained including the shaving in close narrow spaces as aroundthe nostrils employing little or no skill.

Various adaptations and embodiments of the invention can be made to meetparticular conditions and uses, including uses of cutting blades inareas outside the field of close shaving all within the criteria andprinciples of the invention, representative examples being illustratedin the drawings and described hereinafter. Referring to the drawings ingeneral:

FIGURE 1 is a view in perspective of a representative type of bladehaving a guard thereon in the form of a continuous thread spirally woundthereon;

FIGURE la is a fragmentary view of a section of the blade of FIGURE 1 onan enlarged scale showing the threads partially embedded in the extremeblade cutting edge;

FIGURE 1b is an end view of a blade similar to that of FIGURE 1 with thespirally wound thread but in this case with the thread extending in theform of a loop outwardly beyond and spaced from the ultimate cuttingedge of the blade;

FIGURE 2 is a view in perspective of a simple holder with a blade likethat of FIGURE 1 mounted therein;

FIGURE 3 is a view in perspective of a double edge blade with the guardspirally wound thereon similarly to FIGURE 1;

FIGURE 4 is a View in perspective of a simple type of handle adapted tosupport a blade such as that of FIGURE 3;

FIGURE 5 is a vertical section on substantially the plane 5 5 of FIGURE4 illustrating a means for securing the blade in the holder of FIGURE 4;

FIGURE 6 illustrates an application of the invention in a single edgebacked blade of the type commonly referred to as a Gem blade;

FIGURE 7 is an end View of the blade of FIGURE 6;

FIGURE 8 is a further form of the application of a permanently securedthread type guard which in this case is applied solely to the beveledank surface of the sharpened edge in a sinuous form;

FIGURE 9 is a fragmentary cross sectional view on an enlarged scaletaken on a section 9 9 of FIGURE 8;

FIGURE 10 shows a continuous strip blade with the thread guard appliedthereto in the form of a spirally wound continuous thread;

FIGURE 1l is a fragmentary View in largely diagrammatic form showing aholder for a continuous strip blade of the type indicated in FIGURE 10;

FIGURE 12 illustrates a manner of applying the 4threads to a bladeadaptable particularly for injector razors;

FIGURE 13 is a fragmentary cross sectional view taken on the plane 13-13of FIGURE l2 but on an enlarged scale;

FIGURIE 14 is a perspective View in elevation of a holder and bladeassembly the holder in this case embodying a built-in guard or soap bar;and

FIGURE is a View in elevation of a holder supporting a pair of singlecutting edge blades of the character concerned in this inventionarranged in the holder with the cutting dege in opposed relation.

Referring rst to FIGURE l there is illustrated a sample application ofthe principles of the invention to a single edge blade 10 having acutting edge 11. The blade may for example have the dimensions andproportions comparable to those of the present commercial blades of theinjector type. Such a `blade could have a length of about 11/2 inches, awidth of about 1A inch, and a thicknes of about .O10 of an inch.

The guard comprises a thread of small diameter applied in a manner toprovide successive portions extending over and beyond the blade edge.Conveniently this is accomplished by spirally winding the thread 12around the blade 10.

The thread may be of any type of material which is flexible and capableof conforming to the shape of the blade to which it is applied, and iscapable of being pressed against the ultimate cutting edge of the bladeunder normal shaving pressures for example without severing the thread.Fine metal wire as for example of steel is particularly well adapted tothe purpose, but other materials can be employed such as glass berthread or some `synthetic such as a tough grade of nylon. Likewise themanner of securing the thread to the blade may vary dependent in somecasesI upon the kind of material of which it is composed. One method maybe of an adhesive such as one of the epoxy resin adhesives. Normally aband of adhesive extending longitudinally of one or both blade surfacesserves the purpose. The band may be considerably narrower than the bladeand should in any case be spaced from the blade cutting edge. In thecase of a metal thread it may be spot welded to the blade surface asindicated at 13 and each turn of the thread may be welded or the weldingmay be at regularly spaced turns with intervening turns unwelded.Ordinarily it may be suicient with a spirally wound wire to spot weldone or two thread passes at each extreme end of the blade. The bladecutting edge may also be coated with a friction reducing material suchas polytetrauoroethylene coating as disclosed in the United Statespatent to Fischbein No. 3,071,- 856 and the coating applied eitherbefore or after the guard means. Coating after the guard means has beenapplied has the advantage that the thread has an outer coating whichgives a smoother easier shave due apparently to the reduced drag on theskin.

Of critical importance in a shaving blade are the spacing and diameterof the thread. The diameter should he small enough to avoid ironing downof hairs at the areas of the threads and the spacing should be smallenough to prevent too close contact of the skin with the cutting edge.There is, of course, a relation between the diameter of the thread andthe spacing between threads, the larger the diameter of the thread thelarger may be the spacing between threads and conversely, these factorsbeing criti- :ally limited by the necessary requirements of catching allof the hairs without cutting the skin. It has been found that diametersin the range of about .O02 to .O10 of an inch may be employed withwindings in the range of about 30 to 65 per inch, or perhaps a few morewindings with `threads in the smaller end of the range. However, abetter range of diameter size is about .002 to .006 3f an inch, and inmost cases preferably in the range .0025 to .004. Typical examples are athread diameter of `0025 of an inch with windings in the range of about55 to 65 per inch; and a thread diameter of .004 of an inch withwindings in the range of about 30 to 60 per inch. It has been determinedthat human hairs may in some :ases be as large as .010 of an inch indiameter' through :ommonly much smaller. Accordingly for general usagehe net spacing between threads should not be less than `O10 of an inch.It may be noted as examples within the bove criteria a thread diameterof .002 lwith windings of Cit 60 inch results in a clear space betweenadjacent threads of a little less than .015 of an inch; and a threaddiameter of .004 with 45 windings per inch results in a clear space ofabout .018 of an inch. Even with the larger diameter threads the freespace between adjacent threads should preferably not exceed about .035of an inch. Because of the small dimensions involved, particularly thethread diameter, it should be understood that for clarity of disclosuremany of the apparent dimensions and relations indicated in the variousgures are out of proportion.

When the thread is wound spirally around the blade in the form shown inFIGURE l some tension normally will be employed and as a consequence therespective passes over the thin delicate extreme cutting edge will beembedded to some extent as illustrated at 14 in FIGURE la. Thislocalized breaking down of the edge does not affect the cutting sincethe broken area is fully occupied by the thread. Furthermore it has anoverall advantage in that it insures that the threads are maintained inproper spaced relation. The degree of indentation has a bearing ofcourse on the size of thread and spacing to be selected. Assuming athread .004 of an inch in diameter it may be embedded .002 of an inchgiving the guard a net lead in advance of the cutting edge of .002 of aninch. With such a small thread and corresponding small lead the spacingof the threads should be in the lower range.

The blade illustrated in FIGURE l may be mounted in any simple type ofholder of inexpensive form such as that indicated in general in FIGURE 2which has a head 15 and a suitable handle 16 the blade 10 being securedbetween a lower plate 17 and an -upper cap plate 18. Since the blade 10has its own guard the razor does not embody any guard or comb elementsas such, and the cutting edge of the blade 10 extends a substantialdistance beyond the plates 17 and 18. The plate 17 may have a frontlocating means for the blade such as the lugs 19. The blade holder maybe 0f metal 0r plastic and since it can be cheaply made the blade may bepermanently secured in the holder and the razor as a whole disposable.If preferred, however, the cap plate 18 may be hingedly mounted in anysuitable manner enabling the blade 10 to be replaced.

FIGURE 1b shows a modication of the blade of FIG- URE 1 in which thethread guard means 25 has loops 26 extending beyond and free of theultimate cutting edge 27 of the blade 28. In this case the threadmaterial must have a certain amount of rigidity such as would beafforded by a steel wire to avoid substantial deformation under shavingpressure. The lead or distance to which the loops 26 extend beyond thecutting edge 27 will vary dependent upon the circumstances. The threaddiameter and spacing should take into account the amount of such leda.As a general rule, with the added lead the spacing between thread passeswill be greater than when the thread is embedded as in the form ofFIGURES 1 and la. The thread 25 can be spirally wound and secured inplace as described with respect to the blade of FIGURE l. To form theloops 26 the thread winding means may include a small forming pin orwire located in front of the cutting edge over which the successive wireturns are looped, the pin being drawn along parallel to the cutting edgefrom successive loops as the spiral winding progresses. A razorembodying this type of blade would have particular advantage in aso-called Prep razor used in hospitals for removing longer hairpreparatory to an operation, for example.

FIGURE 3 illustrates an application of the principles of the inventionin a double cutting edge razor blade. If the blade is mounted in aholder of the type of that shown in FIGURE 4 it may be quite thin, asfor example about .004 of an inch in thickness. In the case of the blade30 of FIGURE 3 the guard is illustrated as comprising a spirally woundthread 31 such as a ne wire, the type of thread and the conditions anddimensions being of the character described more fully in connectionwith FIG- URE l. Likewise the manner of securing the thread in place maybe in accordance with the description above in connection with FIGURE 1.

Any suitable holder may be provided for the blade and the dimensions andcharacter of the blade and holder made compatible with each other.FIGURE 4 shows a holder having a base support plate 32 and a cap plate33 forming a head mounted on a handle 34, the blade 30 being clampedbetween the two plate members by any suitable means. The razor may be ofmetal or plastic material and of economical construction and manufactureand assembly. The assembly may be permanent and the razor disposable orthe cap 33 may be removable for replacement of the blade. One form ofconstruction is illustrated particularly in FIGURE 5 in which thesupport plate 32 has an integral lug 36 at each end adapted to extendthrough a corresponding notch 37 in the blade and into a depression 38in the cap plate 33, the plate 33 being held in position by a hookportion 39 at each end adapted to snap over and engage around the lowersupport plate 32.

FIGURES 6 and 7 illustrate an application of the principles of theinvention to a single edge backed type of blade of the type sold underthe trademark Gem Typically such a blade comprises the blade proper 41having a U-shaped backing member 42 clamped over the back edge of theblade 41. In this case the guard may be likewise spirally wound on theblade member 41 before being clamped in the backing member 42 orarranged and secured in any suitable manner such as by weaving thethread back and forth and over and around the cutting edge 44. Asillustrated at 45 .for example the thread has a return loop at 46. Oncethe backing member 42 is clamped in place the threads are securely heldalthough additional securing means may be employed such as an adhesivesecuring the portions of the threads outside of the backing member 42.However, it will be understood that the blade 41 may be made muchnarrower than the ordinary Gem blade or the backing member 42 eX- tendedfarther toward the cutting edge 44 eliminating any necessity foradditional securing means for the individual thread portions.

FIGURES 8 and 9 illustrate still another application of a permanentlyattached thread to a cutting blade. In this case the thread has aserpentine or sinuous form and is applied to the ground flank on oneside of the blade the successive threads each being secured in place byappropriate means such as by spot welding at each of the strand portionsas indicated at 52. In the case of Welding, the thread of course wouldneed to be composed of metal. In any event it should have substantialstiffness so as to retain its shape under shaving or other cuttingpressure. As in the case of the extending loop construction of FIG- URElb the degree to which the loops extend beyond the cutting edge 53 willdepend upon the circumstances including particularly the intendedcutting purposes. In the case of a razor blade the projection beyond thecutting edge 53 may appropriately be in the range of up to about 1/32 ofan inch.

Blades of the types shown in FIGURES 6 and 7 and 8 and 9 can be mountedin a simple economical type of holder designed to be disposable orcapable of replacementof the blades as desired. There are various hingedcover razors of a type adapted to receive a blade such as that ofFIGURES 6 and 7 which may be employed in the event it is desired to makethe blade replaceable. Either of these two types of blades can of coursebe employed in a simple razor like that depicted in FIGURE 2.

FIGURES and 11 illustrate the application of a guard of the typeconcerned here in a razor blade of the continuous strip form adapted tobe employed in razors of the general type shown in such patents as Jones2,492,292, Iones 2,591,702 and Nissen 3,262,198. In razors of that typethe strip is a narrow thin band typically about 37/15 of an inch wideand having a thickness in the range of about .0015 to .005 of an inch.

FIGURE 10 shows in plan a section 60 of such a type blade band. Theblade band may have a sharpened cutting edge at either or bothlongitudinal edges. Spirally Wound thereon is the thread 661, thediameter of the thread such as a fine metal wire and the spacing of thecoils being in accordance with the criteria described heretofore inconnection with the blade of FIGURE 1. Likewise the individual coils maybe secured in place by suitable means similar to those described inconnection with FIGURE 1. In other words it may be by means of forexample an adhesive or spot welding. The winding operation normallyinvolves some tension in the thread 'and corresponding indentation ofthe thread at the extreme cutting edges as described in connection withFIGURE la.

FIGURE 11 illustrates in simple and sometwhat diagrammatic form a bladeholder of the general type concerned suitable for mounting the presentblade with its self-contained guard. Accordingly the razor has a headportion 63 with a handle 64 extending therefrom, the head 63 beingadapted to hold a cartridge having a pair of reels 65 and 66 one ofwhich is the initial supply reel and the other the take-up reel, theblade being advanced successively in steps from the supply reel to thetake-up reel lby suitable manually operating means which the foregoingnoted -patents illustrate. In the present case, however, the bladecarries its own guard which functions in shaving but also protects theblade in handling and feeding from one reel to the other, and suitableguides may be provided without danger of injuring the cutting edge suchas the hollow loops 67 and 68 arranged at opposite `ends of thestationary bar 69 on which the blade 60' rides.

Assuming each longitudinal edge of the blade strip is a sharpenedshaving edge the blade strip extends laterally of the supporting bar 69a substantial distance such as at least j/16 of an inch and of course noauxiliary guards or comb in the blade holder are required. If it is asingle cutting edge band the bar 69 may include a vertically extendingflange constituting a back rest and guide against which the unsharpenededge engages. If the blade strip has suiicient stiffness and is undertension the supporting bar 69 may be omitted or at least the mid portionthereof omitted whereby the blade at that region may by moderatepressure be made to conform substantially with the area being shaved.

FIGURES 12 and 13 illustrate a method of applying a guard of the typehere concerned to provide a blade especially adapted for use in aninjector razor and an injector blade dispenser. The blade 70 which maybe of standard injector type and size has threads 71 applied theretowhich may be metal and spirally wound thereon. The blades which at thisstage may be in a continuous strip form are then fed through a weldingmeans which has opposed electrodes such as of disc shape which producewelds at the points 72, 73 located on the ground facets of the blade.

Following that Operation the blade strip `continues through a threadshearing means comprising a pair of opposed cutters adapted to shear thethreads immediately to the rear of the weld points and the portions ofthe threads shown in 'broken lines in FIGURE 12 are freed and removedleaving a blade such as shown in FIGURE 13 having the guard sections71a. It will be noted that the weld points 72, 73 and the guard sections71a are inside the projected planes of the flat surfaces of the bladeand accordingly the blades may be arranged flatwise in full surfaceContact in a stack and dispensed and otherwise handled in the normalmanner.

As illustrated in the various forms thus far described and blade of theinvention embodies its own permanently self-contained guard means. Itmay be desirable in some applications to include in the assembled razora built-in guard or soap bar which may be generally similar to theconventional forms of guards. FIGURE 14 illustrates one such form orapplication. The holder maybe generally similar to that of FIGURE 2 witha head 81 in which is mounted the blade 10, the head including a topplate 82 and a bottom plate 83, the latter having a pair of lugs orhooks 84 against which the cutting edge is engaged. In this case,however, the bottom plate includes an extension in the form of adownwardly curved bar 85 having a slotted opening 86 for escape of soapcorresponding to the guard or soap bar normally embodied in an injectortype razor. Since the blade, in the present case, however, embodies itsown guard, the bar 85 need not be designed and located to serve as aguard primarily but more as an auxiliary means in this respect acting tosmooth down the surface and aid in setting up the hairs for engagementby the blade. Accordingly the spacing between the bar and the blade edgeand the shaving angle are not critical and not required to be held toany close dimension and in general the spacing may be larger than in arazor with a normal plain blade.

FIGURE 15 discloses a razor 90 employing a pair of blades 81, 92 whichmay be equipped with guard means similar to that of FIGURES l and 1a orFIGURE 1b, the blades being arranged with the cutting edges opposed Aclearance space 93 is provided for soap and debris. In this constructionand relation of the elements one guarded blade acts as an auxiliaryguard for the opposite one. In other Words when, for example, the razoris moved to the left in FIGURE l and blade 91 is on a cutting stroke theopposite blade 92 acts as a guard and soap bar. In addition the holdermay be provided with top rounded portions 94, 95 which also are adaptedto bear against the skin 96 as indicated in the figure. Preferably therazor head is freely pivoted to the handle at 97 whereby when thepressure is appropriately applied at the handle the head assumes abalanced position with both rounded bearing portions 94, 95 in contactwith the skin.

Since further forms and modifications of the guarded blade may be madein addition to those disclosed herein and different embodiments of theinvention made without departing from the scope of the invention, it isintended that all matter contained herein shall be interpreted asillustrative and not in a limiting sense I claim:

1. A razor blade with a self-contained guard in the form of a pluralityof spiral windings of a thread firmly attached to the blade, saidwindings being spaced along and extending around the cutting edge, saidthread being of exible material capable of being pressed against therazor blade edge by normalshaving pressure without severance of thethread, said thread having a diameter within the range of .0025 to .006of an inch and the spacing between adjacent windings of said threadbeing uniform and in the range of .010 to .035 of an inch.

2. A razor blade in accordance with claim 1 wherein the thread is ametal wire and is attached to said blade by welding.

3. A razor 4blade in accordance with claim 1 wherein the thread isattached to said blade with an adhesive.

4. A razor blade in accordance with claim 1 Wherein .the diameter ofsaid thread is within the range .0025 to .004 of an inch.

S. A razor blade in accordance with claim 1 wherein the windings of saidthread are embedded for a portion of the diameter of said thread in theextreme cutting edge of said blade.

6. A razor blade in accordance with claim 1 wherein both the bladecutting edge and said thread have a polytetrauoroethylene coatingthereon.

References Cited UNITED STATES PATENTS 1,035,548 t8/1912 Dickenson 30-781,270,783 7/1918 Cartlidge 30--78 2,794,246 6/1957 Marsh et al. 30--77 X3,263,330 8/1966 Ferrara 30-346.56

FOREIGN PATENTS 836,027 10/1938 France.

97,254 6/1898 Germany.

OTHELL M. SIMPSON, Primary Examiner J. C. PETERS, Assistant ExaminerU.S. Cl. X.R. 30-78 gg UNI'IED STATES PATENT OFFICE CETIFICATE OFCRRECTIN patent No. 3,505,734 lDated April 14, 1970 Inventores) AcumulusA. ITEN It is certified .that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

f- Col. 3, line 4, "dege" should read edges -4- Col. 3, lines 5-6"sample" should read simple Col'. 3, line 29, after "be", "of" shouldread by Col. 3, 1:L ne 71, through" should read though Col. 4, line 52,"leds" should read lead Col. 6, line 4, "661" should read 6l Col. 6,line 70, "and" should read the Col. 7, line 13, before "surface" insertVA skin Col. 7, line 20, "81" should read 91 -i- SlGNED Ms I SEALI Aus 1mgm l (SEAL) Mmewlmlr mlm n. Mmmm, JR. Edwm? Gomissione'r of PatentsAOW" A

